Tell us about yourself!
lie detectors are quite famously bunk science. this is why they're inadmissible in court. they exist purely to scare suspects into a confession. you might as well make an arduino powered dowsing rod, it'd be just as useful. also I like how you used the word criminal, rather than suspect. just throw the presumption of innocence right out the window. that kind of attitude is why people get wrongly convicted.
a prius battery is no different than a regular car battery. ideally you would use marine deep cycle batteries. for more life you can also just use another battery bank hooked up in parallel to the existing battery bank.
an electric motor doesn't spin if you're off the throttle, and there's no flywheel to worry about, so the clutch isn't necessary.